The heavy mining industry, such as open pit mining and coal mining, as well as the construction industry, use specialized, often very large, off-road vehicles. The expense and logistics of using these vehicles requires that they can be refueled quickly and safely from both fixed and mobile refueling platforms. This application concerns itself with the system used on the vehicle whose tank that is being filled.
Typical equipment may include a nozzle, receiver, vent, and level-sensing device. The Nozzle is attached to the hose from the fuel pumps and provides a connection to a receiver, which is attached to the fuel tank. Due to the size of the fuel tanks the most common receiver mounting is near the bottom of the tanks. The most common systems use pressuring vents which, when the tank is full, seal off and raise the internal pressure of the tank as the fuel continues to flow in. The pressure increase then shuts off a pressure sensitive nozzle, stopping the flow. This system has been successfully used for over thirty years.
There are however several problems with pressurizing tanks. First operators tend to “top off” the tanks by forcing open the nozzle and end up spilling fuel on the ground through an overflow valve/vent. Second, there is the remote possibility of complete system failure if the shut off valve and the overflow valve fail at the same time. This could overpressure the tank and cause it to split. Third, vehicle manufactures are making their tanks lighter which usually results in a lower pressure handling capability. Fuel spillage is a major environmental concern and tank failure is a major economic concern. Accordingly, it is desirable to provide a fuel shutoff without having to pressurize the tank